Geo-distance sorting should use `POSITIVE_INFINITY` for missing geo points instead of `MAX_VALUE`.

This is consistent with the behaviour of geo sorting in Lucene and also numeric
fields in Elasticsearch.

Closes #20733

core/src/main/java/org/elasticsearch/search/sort/GeoDistanceSortBuilder.java

@@ -586,11 +586,11 @@ public class GeoDistanceSortBuilder extends SortBuilder<GeoDistanceSortBuilder>
                         final SortedNumericDoubleValues distanceValues = GeoDistance.distanceValues(geoPointValues, distances);
                         final NumericDoubleValues selectedValues;
                         if (nested == null) {
-                            selectedValues = finalSortMode.select(distanceValues, Double.MAX_VALUE);
+                            selectedValues = finalSortMode.select(distanceValues, Double.POSITIVE_INFINITY);
                         } else {
                             final BitSet rootDocs = nested.rootDocs(context);
                             final DocIdSetIterator innerDocs = nested.innerDocs(context);
-                            selectedValues = finalSortMode.select(distanceValues, Double.MAX_VALUE, rootDocs, innerDocs,
+                            selectedValues = finalSortMode.select(distanceValues, Double.POSITIVE_INFINITY, rootDocs, innerDocs,
                                     context.reader().maxDoc());
                         }
                         return selectedValues.getRawDoubleValues();

core/src/test/java/org/elasticsearch/search/sort/GeoDistanceIT.java

@@ -375,7 +375,7 @@ public class GeoDistanceIT extends ESIntegTestCase {
         assertHitCount(searchResponse, 2);
         assertOrderedSearchHits(searchResponse, "1", "2");
         assertThat(((Number) searchResponse.getHits().getAt(0).sortValues()[0]).doubleValue(), closeTo(462.1d, 10d));
-        assertThat(((Number) searchResponse.getHits().getAt(1).sortValues()[0]).doubleValue(), equalTo(Double.MAX_VALUE));
+        assertThat(((Number) searchResponse.getHits().getAt(1).sortValues()[0]).doubleValue(), equalTo(Double.POSITIVE_INFINITY));
 
         // Order: Desc
         searchResponse = client().prepareSearch("test").setQuery(matchAllQuery())
@@ -385,7 +385,7 @@ public class GeoDistanceIT extends ESIntegTestCase {
         // Doc with missing geo point is first, is consistent with 0.20.x
         assertHitCount(searchResponse, 2);
         assertOrderedSearchHits(searchResponse, "2", "1");
-        assertThat(((Number) searchResponse.getHits().getAt(0).sortValues()[0]).doubleValue(), equalTo(Double.MAX_VALUE));
+        assertThat(((Number) searchResponse.getHits().getAt(0).sortValues()[0]).doubleValue(), equalTo(Double.POSITIVE_INFINITY));
         assertThat(((Number) searchResponse.getHits().getAt(1).sortValues()[0]).doubleValue(), closeTo(5286d, 10d));
     }
 
@@ -523,9 +523,9 @@ public class GeoDistanceIT extends ESIntegTestCase {
         assertFirstHit(searchResponse, hasId("4"));
         assertSearchHits(searchResponse, "1", "2", "3", "4");
         assertThat(((Number) searchResponse.getHits().getAt(0).sortValues()[0]).doubleValue(), closeTo(8572.0d, 10d));
-        assertThat(((Number) searchResponse.getHits().getAt(1).sortValues()[0]).doubleValue(), equalTo(Double.MAX_VALUE));
-        assertThat(((Number) searchResponse.getHits().getAt(2).sortValues()[0]).doubleValue(), equalTo(Double.MAX_VALUE));
-        assertThat(((Number) searchResponse.getHits().getAt(3).sortValues()[0]).doubleValue(), equalTo(Double.MAX_VALUE));
+        assertThat(((Number) searchResponse.getHits().getAt(1).sortValues()[0]).doubleValue(), equalTo(Double.POSITIVE_INFINITY));
+        assertThat(((Number) searchResponse.getHits().getAt(2).sortValues()[0]).doubleValue(), equalTo(Double.POSITIVE_INFINITY));
+        assertThat(((Number) searchResponse.getHits().getAt(3).sortValues()[0]).doubleValue(), equalTo(Double.POSITIVE_INFINITY));
 
         try {
                 client().prepareSearch("companies").setQuery(matchAllQuery())